(CNN) -- Defense Secretary Chuck Hagel said Sunday that he's open to a review of the U.S. military's policy prohibiting transgender individuals from serving.

"I do think it continually should be reviewed," Hagel told ABC's Martha Raddatz.

"I'm open to those assessments, because again, I go back to the bottom line: Every qualified American who wants to serve our country should have an opportunity, if they fit the qualifications and can do it," he said.

President Barack Obama signed a bill repealing the U.S. military's "don't ask, don't tell" policy in late 2010 setting off a transition process to allow gays and lesbians to serve. But transgender individuals are still banned from serving.

"The issue of transgender is bit more complicated because it has a medical component to it," Hagel said. "These issues require medical attention. Austere locations where we put our men and women in many cases don't always provide that kind of opportunity."

A report this year from a commission co-chaired by former U.S. Surgeon General Joycelyn Elders found no "compelling medical rationale" for the Pentagon's ban on transgender military service.